Secondary pelvis and perineum Flashcards
What forms the pelvis?
hip bones, sacrum, coccyx
What are the pelvis functions?
transfers weight of the upper body to the lower body, withstands compression, houses and protects pelvic viscera
What is the pelvic brim?
Divides true and false pelvis (false - bigger circle) (true - smaller inlet)
What’s the difference between true and false pelvis?
false “greater” – loops of the ileum, sigmoid colon
true “lesser” – urinary bladder and reproductive organs
What are the hip bones?
ilium, ischium, pubis
What is the obturator foramen?
between ischium-pubis
What is the acetabulum?
where the femur head rests
What does the lumbar vertebrae do?
1) formation of posterior wall
2) allows flexion and extension
3) curvature or lordosis
4) site of fracture
What are the four joints of the pelvis?
1) sacrococcygeal
2) lumbrosacral
3) sacroiliac
4) pubic symphysis
What are the main ligaments of the hip bones you can see from the sagittal cut?
obturator membrane, sacrospinous ligament, sacrotuberous ligament
What are the main ligaments of the hip bones you can see from a posterior cut?
interosseous sacroiliac ligament (horizontal)
posterior sacroiliac ligament (vertical), Sacrotuberous ligament (diagonal)
What are the main ligaments of the hip bones you can see from an anterior cut?
Iliocolumbar ligament (horizontal), anterior sacroiliac ligaments (wide horizontal), sacrospinous ligament (low horizontal)
How is the greater sciatic foramen and lesser sciatic foramen separated?
sacrospinous ligament
What makes the second border of the lesser sciatic foramen?
sacrotuberous ligament
What exits out of the greater sciatic foramen?
superior gluteal nerve and artery, piriformis, interior gluteal nerve and artery, and the sciatic nerve
What exits out of the lesser sciatic foramen?
Internal pudendal artery and vein, pudendal nerve, obturator internus tendon, nerve to obturator
What is the lumbosacral plexus?
both lumbar and sacral plexus formed by anterior rami located on posterior wall, adjacent to spine, imbedded and into the psoas major muscle
What nerves make up the lumbosacral plexus?
(spinal nerves L4 to L5 and S1 to S4)
What are the two main nerves from the sacral plexus?
sciatic and pudendal
What is the sciatic nerve?
largest nerve of the body – L4-S3, converges, most commonly passing through greater sciatic foramina
What is the pudendal nerve?
main nerve of perineum and chief sensory nerve of external genitalia, S2-S4, skin, terminal parts of reproductive, urinary & digestive tracts
What is the pudendal plexus?
lying on posterior wall of pelvis, formed by branches of S2, S3, S4, S5, coccgeal nerve
What is the coccygeal plexus?
innervation of cocygeus, part of levator ani, sacrococcygeal joint, and supplies skin between tip of coccyx and anus
What do sympathetic fibers produce?
contraction of internal genital organs during orgasm and inhibit rectal peristalsis
What do parasympathetic fibers stimulate?
contraction of rectum/bladder for defecation and urination; erection
What are the 4 female pelvic arteries?
paired internal iliac artery, median sacral artery, superior rectal, paired ovarian artery
What are the 3 male pelvic arteries?
paired internal iliac artery, median sacral, superior rectal
What are the branches of the external iliac artery?
superficial gastric artery, inferior epigastric artery, superficial circumflex, superficial external pudendal artery, deep external pudendal
What are the branches of the internal iliac artery?
iliolumbar, lateral sacral, gluteal (superior/inferior), pudendal, inferior vesical (uterine), middle rectal, vaginal, obturator, umbilical
What is the pelvic floor?
support pelvic viscera and formed by pelvic diaphragm: levator ani, small coccygeus, covering fascia, incomplete anteriorly
What are the 3 parts of the levator ani muscle?
puborectalis -> pubococcygeus -> iliococcygeous
What muscle supports the vagina and prostate?
pubococcygeus muscle
What is the coccygeus muscle?
coccyx -> ischial spine; posterior sheet that forms levator ani
tail that would wag
support and flexes the coccyx
What causes pelvic floor dysfunction?
pudendal nerve (S2-S4) compression and stretching OR lumbosacral plexus injury (levator ani fails to reflexively contract with squeezing)
What does the obturator internus do?
rotates thigh LATERALLY, helps abduct thigh
How is the obturator internus supplied?
internal pudendal and superior/inferior gluteal artery. POSTERIOR cocyxx
Does the obturator have a membrane?
yes - nerve, artery and vein pass through
What is the piriformis?
anterior pelvis to 2-4th segments of sacrum; attached to tip of greater trochanter and lateral rotator with extension, abductor
What is subperitoneal endopelvic fascia?
connective and fatty tissue that fills the space between organs and forms ligaments: cardinal, retrouterine (uterus!) and hypogastric sheath
What is the perineum?
external surface and shallow compartment
What is the urogenital diaphragm?
muscular membrane perforated by urethra and vagina, with fibrous mass between urethra/anal canal; final support of pelvic viscera in women
Where is the superficial perineal pouch?
where the clitoris is
Where is the deep perineal pouch?
deep and around area of urethra
How do the ureters enter the bladder?
through muscular wall with a one way valve and the detrusor muscle tightens the bladder to prevent reflux
How is the bladder innervated?
superior vesical artery (umbilical) and inferior vesical artery (internal iliac)
How long is the female urethra?
3-4 cm long; supplied by internal pudendal and vaginal arteries
What’s different about the male urethra?
transports semen and urine, four parts, and the intramural (prevents semen from entering bladder during ejaculation)
What does the ductus deferens do?
carries sperm testis->ejaculatory duct
seminal vesical adds fluid and enters prostate and puts some milky fluid and opens the prostatic urethra
What is the prostate?
size of a walnut, has its own sheath, participates in ejaculation
What is the bulbo-urethral gland?
in external urethral sphincter (right before spongy urethra) that has mucus-like secretion during arousal to protect from acidic urine
How long is the vagina?
7.5cm long, between bladder and rectum
What is the Pouch of Douglas?
rectouterine pouch triangular made of fornices
What does the fundus do in pregnancy?
expands
What are the walls of the uterus?
serous - peritoneum and fat, muscular - myometrium, smooth muscle proliferation during pregnancy, mucosa - endometrium
What is the broad ligament?
folds of peritoneum that attaches uterus to side walls of pelvis which consists of mesovarium (covers ovary), mesometrium (rest), mesosalpinx (uterine tube and hangs)
What’s the ovarian ligament?
in broad ligament but attaches ovary to uterus
What is the round ligament?
continuous with ovarian ligament and holds fundus of the uterus forward
What are the suspensory ligaments?
peritoneal folds that cover supply
What are uterosacral ligaments?
connects isthmus of uterus to sacrum
What is “water under the bridge”?
uterine artery crosses over ureter
How does the ureter run with internal iliac artery?
medial to and parallel
What are fallopian tubes?
fimbriae -> infundibulum -> ampulla -> isthmus
What is the communication between peritoneal cavity and outside environment?
ostium surrounds portion of ovary (aka fallopian tubes)
What is key about the ovary drainage?
right ovarian -> IVC
left ovarian -> left renal vein
Most common cause of cervical cancer?
HPV
Where does cervical cancer metastasize first?
parametrial -> obturator -> pelvic -> para-aortic
Where does uterine cancer metastasize first?
pelvic nodes or para-aortic
Where does ovarian cancer metastasize first?
pelvic or para-aortic nodes
What is the rectum?
continuous with sigmoid colon and anal canal; approx S3, end tip of coccyx
What is the ichio-anal fossae?
space with fat and fascia that makes rectal abscesses very concerning
What do you need to watch out for near the anal canal?
pudendal horizontal canal (Alcock’s canal) with vessels
What is the pectinate line?
where the type of tissue changes, commonly at risk of cancer and different vasculature
What are the parts of the body of the penis?
corpora cavernosa and corpus spongiosum; supplied by internal pudendal and dorsal nerves
What may the penis have?
prepuce
What causes an erection and subsequent ejaculation?
pudendal nerve, pelvic splanchnic nerves
What nerve first leaves the pelvic via the greater sciatic foramen and then re-enters via the lesser sciatic foramen?
pudendal nerve
What aids in ejaculation and assists in proper positioning of the fetus head?
levator ani muscle
What is SADPUCKER?
S-subadrenal glands
A-aorta/IVC
D- duodenum
P-pancreas
U-ureters
C-colon
K-kidneys
E-esophagus
R-rectum
Where is the rectosigmoid junction?
S3
